Percent Relative Standard Deviation Research Articles

Application of sol‐gel universal sorbent coated fabric phase sorptive extraction membranes in combination with high‐performance liquid chromatography‐ultraviolet detection to monitor endocrine‐disrupting chemicals in milk and environmental water samples

AbstractHere, we deployed sol‐gel universal sorbent‐coated fabric phase sorptive extraction membranes in tandem with high‐performance liquid chromatography equipped with an ultraviolet detector (HPLC‐UV) for the analysis of 10 endocrine‐disrupting chemicals (EDCs). Due to the varying polarities of the studied compounds indicated by their octanol/water partition coefficient ‘log Kow’ (1.47–5.07), the extraction membrane was designed with different functionalities that are capable of simultaneous interaction with compounds of diverse natures including polar, non‐polar, and ionic species via sol‐gel sorbent coating technology. An isocratic mode of HPLC‐UV at 55:45% acetonitrile:water (v/v) on a reverse phase C18 Zorbax column (5 μm, 150 mm, 4.6 mm) was used for the separation and quantitation. Calibration curves were found linear between 25 and 2000 ppb for all compounds except cortisone in the range of 25–1000 ppb which provided an R2 value above 0.9940 in all cases. The intra‐day reproducibility and inter‐day reproducibility were found in the range of 1.2–12.8 and 0.2–14.1 (expressed as percent relative standard deviation), respectively. The validated method was finally deployed for the analysis of environmental water and milk samples with estradiol showing the highest concentrations among the studied compounds.

A highly sensitive micelle-enhanced synchronous spectrofluorimetric determination of the recently approved co-formulated drugs, bilastine and montelukast in pharmaceuticals and human plasma at nanogram levels.

In this study, the simultaneous determination of bilastine and montelukast, two recently approved co-formulated antihistaminic medications, was accomplished using a quick, sensitive, environmentally friendly, and reasonably priced synchronous fluorescence spectroscopic approach for the first time. Enhancement of the method's sensitivity down to nanogram levels was achieved by the addition of sodium dodecyl sulfate (1.0% w/v) as a micellar system. According to the results, bilastine and montelukast's fluorescence was measured at 255.3 and 355.3nm, respectively, using Δλ of 40.0nm and distilled water as a green diluting solvent. With respect to the concentration ranges of bilastine (5.0-300.0ng/ml) and montelukast (50.0-1000.0ng/ml), the method showed excellent linearity (r ≥ 0.9998). The results showed that the suggested method is highly sensitive, with detection limits of 1.42 and 13.74 ng/ml for bilastine and montelukast, respectively. Within-run precisions (intra- and interday) per cent relative standard deviations (RSD) for both analytes were <0.59%. With high percentage recoveries and low percentage RSD values, the designed approach was successfully applied for the simultaneous estimation of the cited medications in their dosage form and human plasma samples. To evaluate the green profile of the suggested method, an analytical GREENNESS metric approach (AGREE) and green analytical procedure index (GAPI) metric tools were used. These two methods for evaluating greenness confirmed that the developed method met the highest number of green requirements, recommending its use as a green substitute for the routine analysis of the studied drugs. The proposed approach was validated according to ICHQ2 (R1) guidelines.

Validation and measurement uncertainty of the determination of 24 elements in drinking water using ICP-MS

Abstract In this study, the concentrations of 24 elements, which are suspicious to be found in drinking and utility waters for the province of Antalya/Turkey, were determined using an inductively coupled plasma-mass spectrometer (ICP-MS). Validated methods with a low limit of detection are required to analyze such waters. The method was validated considering selectivity, limits of detection and quantification, sensitivity, linearity, operating range, accuracy, precision, and measurement uncertainty. All monitored isotope calibration plots had a correlation coefficient of 0.9994 or higher. According to the results of recovery, the expected results of all element isotopes were determined in the range of 94–104%. The average precision quantities for items were calculated as percent relative standard deviation (%RSD) between 0.10 and 2.31%. The analytical method provided here for detecting the concentrations of 24 elements in drinking water samples with demonstrated traceability and estimated uncertainty can yield reliable and internationally comparable results.

ANALYTICAL UV SPECTROSCOPY METHOD DEVELOPMENT AND VALIDATION STUDIES FOR SIMULTANEOUS ESTIMATION OF METFORMIN HCL AND QUERCETIN

In the current investigation, we have designed and assessed a simple and swift analytical approach employing UV spectroscopy for the simultaneous quantification of the analytes metformin and quercetin with excellent precision and accuracy. The wavelengths of interest are the wavelengths at which both the drugs show maximum absorbance: 233 nm for metformin and 256 nm for quercetin. Linearity study, conducted in methanol and phosphate buffer, yielded a correlation coefficient (r2 ) of 0.99. The validation study for the developed method was conducted in accordance with ICH Q2 R1 guidelines. The percent recovery was 95% to 105%, and the percent relative standard deviation was &lt;2, demonstrating the accuracy and precision of this method. This method can be applied to analysis of the two compounds in fixed dose formulations using simple UV spectroscopy.

Development of a universal sol–gel sorbent for fabric phase sorptive extraction and its application in tandem with high performance liquid chromatography-ultraviolet detection for the analysis of phthalates in environmental and drinking water samples

Most sorbent-based sample preparation methods are designed to interact with a class of analytes i.e., a polar sorbent for polar analytes, a non-polar sorbent for non-polar analytes, an ion-exchange sorbent for ionized compounds. A big challenge surfaces when making a choice of an appropriate sorbent when there is a mixture of compounds of varying polarities and ionization states in the complex sample matrices. Hence, the aim of this study was to develop a universal sol–gel sorbent coating for fabric phase sorptive extraction that would effectively and simultaneously extract polar, nonpolar, organic acids and bases via different intermolecular/interionic interactions. The universal sol–gel sorbent coated fabric phase sorptive extraction membrane was created by exploiting sol–gel surface coating technology to implant different functional moieties, ion exchanging ligands and an organic polymer that results in a 3-D organic–inorganic hybrid structure on the fabric substrate with a high level of selectivity/affinity for the target compounds. The preconcentrated extracts containing the isolated phthalates after the fabric phase sorptive extraction procedure were injected into the high-performance liquid chromatography-ultraviolet detection (HPLC-UV) system for the quantification. The FPSE-HPLC-UV method demonstrated a linear range between 50 and 1000 ng/mL for dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diallyl phthalate, benzyl butyl phthalate, 1–10000 ng/mL for di-n-heptyl phthalate, 1–5000 ng/mL for di-n-heptyl phthalate, 10–5000 ng/mL for di-n-ethyl hexyl phthalate and 100–7500 ng/mL di-n-octyl phthalate. The intra-day and inter-day reproducibility (in terms of percentage relative standard deviation, %RSD) did not exceed 13.6. This method proves to be a selective, accurate, reproducible, cheap, and fast analytical approach for the quantitative and qualitative determination of the phthalates which is useful in crafting regulations for phthalates content in beverages and juices as well as in environmental monitoring.

Smartphone digital image colorimetry combined with dispersive solid-phase microextraction for the determination of boron in food samples.

Simple, inexpensive and accurate analytical methods are in high demand. Dispersive solid-phase microextraction (DSPME) was used in combination with smartphone digital image colorimetry (SDIC) to determine boron in nuts as an approach replacing existing costly alternatives. A colorimetric box was designed to capture images of standards and sample solutions. ImageJ software was used to link pixel intensity to the analyte concentration. Under optimum extraction and detection conditions, linear calibration graphs were obtained with coefficients of determination (R2) above 0.9955. Percentage relative standard deviations (%RSD) were below 6.8%. The limits of detection (LOD) ranged between 0.07 and 0.11μgmL-1 (1.8 to 2.8μgg-1), which were sufficient for detection of boron in nut samples (i.e., almond, ivory, peanut and walnut), with percentage relative recoveries (%RR) between 92.0 and 106.0%.

Development and Validation of an Innovative Stability Indicating Method Using UVSpectroscopy Techniques for Ritonavir in Bulk Drug and Pharmaceutical Dosage Forms

Ritonavir is a protease inhibitor used to treat HIV/AIDS. It is seldom employed for its antiviral activity but instead as a booster for other protease inhibitors. Our study's significant objective is to develop a new, simple, accurate, precise, and reproducible UV spectrophotometric approach for investigation by apotheosis to analyze ritonavir. Three alternative simple, accurate, and precise UV spectrophotometric techniques-the, zero-order (method A), first-order (method B), and the area under the curve (method C) spectrophotometric methods have been established for the measurement of ritonavir in bulk and pharmaceutical dosage. The drug was dissolved in ethanol, and then 0.063 M Phosphate buffer solution (pH 7.0), and the observed λmax are 271 nm for the zero-order spectrophotometric method (method A), 258 nm for the first-order spectrophotometric method, 260–281 nm for the area under the curve spectrophotometric method (method C). Under the optimum conditions, linear relationships with good correlation coefficients 0.9994–0.9999 were found between the reading and the corresponding concentration of the drug in the range of 10-50 μg/ml. The proposed methods can detect the analyte in the lower limits of 0.24 to 0.38 μg/ml. The precision of the methods was satisfactory, and the percentage relative standard deviation values did not exceed 2%. The proposed methods were successfully applied to the analysis of ritonavir in its bulk and commercial formulations with good repeatability and reproducibility; the label claim percentages ranged from 99.56 to 99.64 ± (0.34-0.63) % w/v. The research findings of the current approach were shown to be more accurate and trustworthy for ritonavir in pharmaceutical dosage forms and bulk pharmaceuticals compared to those previously reported by the spectrophotometric approaches. The proposed techniques can be used for routine inspections without causing any interference from excipients or other substances because of the quick and repeatable analysis.

A sensitive ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of assay and trace-level genotoxic tosylate analogs (methyl and ethyl) in empagliflozin and its tablet dosage forms.

This study performed the simultaneous quantification of assay and two alkyl sulfonate (tosylate) analogs of empagliflozin (EGZ), specifically methyl 4-methyl benzene sulfonate (MMBS) and ethyl 4-methyl benzene sulfonate (EMBS) in EGZ, and its finished dosage form using an accurate and sensitive ultra-performance liquid chromatography-mass spectrometry method. The separation was achieved on a Waters Acquity BEH Shield RP18 (100 ×2.1mm, 1.7μm) column in gradient elution mode with 0.1% formic acid and acetonitrile as the mobile phases and a flow rate of 0.5mL/min. For simultaneous quantification, the multiple reaction monitoring technique was utilized. The procedure was successfully validated in accordance with the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines. The peak areas of both impurities, along with their concentrations, exhibited a good relationship with Pearson's correlation coefficient (R), which was >0.999 in the range of 0.3-6ppm with an EGZ concentration of 2mg/mL. The percentage recoveries from the limit of quantitation (LOQ) to 200% to the specification level were in the range of 94.82%-102.92%, whereas the percentage relative standard deviation (%RSD) was <2. Therefore, this method is rapid and accurate to quantify MMBS, EMBS, and EGZ assay simultaneously from the marketed tablet dosage forms of EGZ for commercial release and stability sample testing.

Validation of UHPLC-ESI-MS/MS Method for Determining Steviol Glycoside and Its Derivatives in Foods and Beverages.

The aim of this study was to validate a method for determining nine types of steviol glycoside and its derivatives in food and beverage products, using ultrahigh-performance liquid chromatography tandem mass spectrometry with electrospray ionization (UHPLC ESI MS/MS). The performance characteristics of the analysis method were determined along with their suitability for the intended use. Coefficient of determination (R2) calibration curves from 0.2 to 1.0 mg L-1 were in the ranges of 0.9911-0.9990, 0.9939-1.0000 and 0.9973-0.9999 for a beverage, yogurt and snack, respectively. Intra-day precisions in terms of percent relative standard deviation (% RSD) of concentration, at 0.2, 0.5 and 1.0 mg L-1, for the beverage, yogurt and snack were lower than 15% (1.1-9.3%). At all concentrations, percentage recoveries were in the accepted range of 70-120%. For the matrix effect study, matrix-matched calibration was used for all compounds, obtaining a linear concentration range from 0.2 mg L-1 to 1.0 mg L-1. Almost all matrix-matched results presented as percentage recoveries were within the accepted range of 80-120%. The limit of detection (LOD) for steviol glycosides ranged from 0.003 to 0.078 μg g-1, while the limit of quantitation (LOQ) ranged from 0.011 to 0.261 μg g-1. These results indicate that the modified test method can be applied to determine the presence of steviol glycoside and its derivatives in a wide range of sample matrices.

Reversed phase HPLC method development and validation for the analysis of amlodipine besylate in tablets dosage form and human plasma

Introduction: Several analytical methods for quantitative determination of amlodipine either in pharmaceuticals or biological fluids have suffered different setbacks. Therefore, we aimed at developing a cost effective, simple, robust, and sensitive reversed phase high performance liquid chromatography (RP-HPLC- UV) method for quantification of amlodipine in dosage form and in human plasma. Method: The separation was performed on an analytical column 150 mm x 4.6 mm i.d., Agilent Eclipse XDB C18 Column packed with 5 μm particle size and protected by a guard column (30 mm x 4.6 mm i.d.). The mobile phase composition contained acetonitrile: phosphate buffer (25 mM KH2PO4) adjusted to pH 3.1 with orthophosphoric acid in the ratio of 45:55 v/v. The flow rate was 1.2 mL/min and the UV detector was set at a wavelength of 240 nm. The column was maintained at ambient temperature. Results: The calibration curve gave good linearity in the concentration range studied. The column efficiency was highly evident by high theoretical plates and small height equivalent to theoretical plate (HETP). The percent relative standard deviation (% RSD) was less than 3% in the inter- and intra-day o assay. Amlodipine, 50 ng/mL in plasma stored frozen at -80 C was stable There was no statistical difference in the precision of amlodipine assayed after 12 months when compared to the initial assay (P&gt;0.05). The % recovery of amlodipine in human plasma was 97.79±0.17% to 99.52±0.63%. Conclusion: The new RP-HPLC method is sensitive, reproducible, precise, accurate and robust. We conclude that the method is suitable for estimation of amlodipine besylate in human plasma for pharmacokinetic studies and assay of pharmaceutical dosage form

Development of Electrometer for Dose Area Product (DAP) Measurement to Monitor Patient Dose in Radiography Examinations

This study aimed to develop an electrometer for dose area product (DAP) measurement to monitor patient doses on X-ray radiography examinations. The electrometer was developed based on the Atmega8535 microcontroller as the processing unit. This electrometer was operated at 12 volts of direct current (DC) and controlled by buttons for navigation. The system (i.e. in-house electrometer and DAP meter) was carefully designed so that it can easily perform calibration and dose measurements. The system was evaluated at variations of tube voltage, tube current, and exposure time. The developed system results in high accuracy and precision as indicated by low percent error (PE) and relative standard deviation (RSD) compared to standard system. The highest PE and RSD are 1.69% and 1.42% for tube voltage variation, 3.85% and 3.58% for tube current variations, and 12.10% and 0.92% for exposure time variations. In conclusion, the developed system is feasible to be used as a patient dose measurement tool to meet the needs of radiation protection to achieve the principle of “as low as reasonably achievable (ALARA).

Pre-concentration of pesticides in water using isophorone diamine multiwalled carbon nanotubes-based solid-phase extraction technique and analysis by gas chromatography–mass spectrometry

The existence of pesticides in water at ultra-trace levels necessitates the use of a suitable pre-concentration method for their detection. The objective of this study was to develop an ultra-synthetic adsorbent to extract chlorpyrifos (CPF) and imazalil (IMA) pesticides in water. X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy confirm that both oxidised and isophorone diamine multiwalled carbon nanotubes (IPD-MWCNTs) were successfully prepared with an intact structure; which was further confirmed by transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS). The Brunauer–Emmet–Teller (BET) showed a high surface area of both oxidised and IPD-MWCNTs, which is linked to the formation of additional active sites. TGA further showed that the nanocomposites were highly stable within the pesticides quantification operating temperature. CPF and IMA were recovered using a low dosage of IPD-MWCNTs adsorbent (0.030 g) and eluted by a combined solvent (ethanol and chloroform (50:50, v/v)). The adsorbent was reusable over seven repeated cycles, with an acceptable percentage relative standard deviation (%RSD) ranging from 3 to 8%. The IPD-MWCNTs adsorption sites are highly stable and cannot be easily fouled, as compared to that of oxidised MWCNTs. Lower limits of detection (LOD) and quantification (LOQ) for CPF (0.026 and 0.078 µg.L−1) and IMA (0.033 and 0.100 µg.L−1) were achieved. Better recoveries for both analytes at low and high concentrations (as well as in real water samples) were obtained by IPD-MWCNTs whereas a conventional adsorbent (i.e. polymeric reverse phase) can only achieve better recoveries at high concentrations.

Speciation analysis of inorganic arsenic in water samples using thiol-ligand and cotton fibres followed by ICP-OES determination

ABSTRACT This research aimed to develop a method for the speciation analysis of arsenic species, including As(III) and As(V) in environmental samples. Cotton fibres and thiol-ligands, including ammonium pyrrolidine dithiocarbamate (APDC), L-cysteine, and diethyldithiocarbamic acid (DDTC), were used as a simple solid phase extraction (SPE) followed by arsenic determination using inductively coupled plasma optical emission spectrometry (ICP-OES). The separation parameters were thoroughly investigated, including pH, thiol-ligand concentration, cotton fibre amount, type of eluents, and flow rate. It was found that As(III) could be efficiently separated from As(V) by using a column containing 0.5 g cotton fibres and 0.1% APDC under pH 2. As(III) was then eluted using 5 mL of mixed solvents of 4 M HNO3, 4 M HCl, and 0.5 M H2O2 (1:1:1 v/v). The method was then used to perform a speciation analysis of arsenic in model solutions with As(III) and As(V) concentrations ranging from 10–1000 μg/L. The results showed good recoveries of both arsenic species at 80–120% with a satisfactory percentage relative standard deviation (%RSD). The developed method was subsequently applied for arsenic speciation analysis in the environmental samples, including natural and wastewater samples.

Validated Analytical Method for Multicomponent Analysis of Famotidine and Ofloxacin in Bulk drug and Tablet Formulation by using UV-Visible Spectrophotometer and RP-HPLC

A simple, sensitive, accurate, precise, and reproducible UV- spectrophotometric method and RP-HPLC methods were developed and validated for the estimation of Famotidine and Ofloxacin in bulk drug and pharmaceutical formulation. The Linearity regression was detected and shows a good linear relationship; in the concentration range of 10-50µg/mL (R2 &gt;0.9908) for famotidine and 10-50µg/mL (r2&gt;0.9913) for ofloxacin. The UV – spectrophotometric estimation was carried out by the first-order derivative spectrophotometric method and absorbance were recorded at 273 and 280nm. Beers range were found to be 5-50µg/mL, respectively for both drugs while, correlation coefficient r2 &gt; 0.9988 and 0.9941 for famotidine and ofloxacin. The isoabsorptive point was found to be 274nm in HPLC optimized mobile phase composition, potassium dihydrogen orthophosphate: methanol (60:40). Chromatographic condition consisted of mobile phase potassium dihydrogen orthophosphate buffer pH 2.3, methanol (60:40v/v), run time 30 min, C-18 column (ODS Hypersil) and flow rate 0.8mL/minute. The retention time for famotidine and ofloxacin were found to be 2.44 min, 7.99 min. respectively, and detection at λmax 274nm for both drugs (overlain spectra). The UV methods and RP-HPLC showed good reproducibility and recovery with the percent relative standard deviation (RSD) less than 5%. As per ICH guidelines, the developed method was validated for linearity, accuracy, precision, Sandell's sensitivity, and repeatability proving its utility in the estimation of famotidine and ofloxacin in house tablet formulation.

Rapid ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of three characteristic urinary saccharide metabolites in patients with glycogen storage diseases (type Ⅰb and Ⅱ)

Urinary 1,5-anhydroglucitol (1, 5-AG), 6-α-D-glucopyranosyl-maltotriose (Glc4) and maltotetraose (M4) are important biomarkers for glycogen storage disease (types Ib and Ⅱ). This study aimed to develop and validate an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to detect these three urinary saccharide metabolites. Urine samples were diluted and then analyzed. Chromatographic separation was performed on an Acquity™ UPLC Amide column (2.1 × 100 mm, 1.7 μm) with gradient elution. The quantitation of analytes was achieved on a 5500 Qtrap mass spectrometer using negative multiple reaction monitoring (MRM) mode. The calibration curves for all analytes were linear over the range of 0.500 to 100 μg/mL with a correlation coefficient, R2 ≥ 0.999. The percent relative standard deviations (RSD%) were ≤12.8%, and the percent relative errors (RE%) were in the range of −11.7%–11.0%. The relative matrix effects of all analytes were between 87.2% and 104% with RSD% < 3.10% across three concentrations. The developed analytical method was simple, accurate, and reliable for rapid and simultaneous analysis of these three urinary saccharide metabolites. It was applied to healthy volunteers and patients. To our knowledge, it was the first validated assay for urinary maltotetraose quantification. This work provides support for exploring the potential of maltotetraose as a biomarker for Pompe disease.

Development and validation of a method based on liquid chromatography-mass spectrometry for comprehensive profiling of phenolic compounds in rice

The consumption of rice grains containing phytochemicals associated with antioxidant activity can potentially reduce the risk of chronic diseases. These phytochemicals, which include phenolic acids, anthoxanthins, and anthocyanins, are present in both free and bound forms in rice grains. However, there is limited documentation on the development of a method for determining the simultaneous amount of both free and bound phenolic compounds using sensitive analytical techniques. To address this gap, a study was conducted to develop and validate a liquid chromatography-mass spectrometric detection method for quantifying eighteen phenolic compounds in rice grains, both in free and bound forms. Paracetamol was used as the internal standard to minimize the effect of matrix interferences. The method was validated by measuring its working range, linearity, accuracy, precision, limits for detection and quantification, robustness, and expanded uncertainty. The method has a wide working range of 1.0 to 30.0 mg/kg for each phenolic compound and good linearity, with regression coefficients of calibration graphs greater than 0.999. Accuracy was determined using the recoveries after fortification at three concentration levels, which were in the range of 83.1 to 101.2%. Precision was expressed as a percentage of relative standard deviation (%RSD), which was below 7.62% for all determined phenolic compounds. The detection limits (LoD) and quantification limits (LoQ) ranged between 0.53 and 0.75 mg/kg and 0.54–0.77 mg/kg, respectively. The percentages of expanded uncertainties at the coverage factor of 2 (k = 2) were below 11.7%. The method was also evaluated for its robustness by obtaining recoveries at satisfactory levels for three different kinds of cereal; wheat, maize, and millet. The validated method is an accurate and reproducible approach for the simultaneous determination of phenolic compounds present at low levels in a complex matrix such as rice. The study also found that the phenolic profiles vary among rice genotypes, which can significantly impact human health by varying the nutraceutical properties of rice grains as health-promoting aspects.

Quantification of trace fenuron in waste water samples by matrix matching calibration strategy and gas chromatography-mass spectrometry after simultaneous derivatization and preconcentration.

This study presents a highly sensitive and accurate analytical strategy for the determination of fenuron in wastewater samples using gas chromatography-mass spectrometry (GC-MS). Simultaneous derivatization and spray-based fine droplet formation-liquid phase microextraction (SFDF-LPME) method was developed and performed to achieve low detection limits. The parameters of the derivatization and SFDF-LPME method were optimized by univariate approach to improve sensitivity and selectivity. Under the optimum SFDF-LPME-GC-MS conditions, the limit of detection (LOD) and limit of quantitation (LOQ) were found to be 0.15 and 0.49 mg/kg, respectively. In addition, the linear range was calculated as 0.51-24.50 mg/kg. Recovery studies were carried out on wastewater samples to determine the accuracy of the developed method and its applicability to real sample matrix. Matrix matching calibration strategy was applied to eliminate/reduce any possible interference effects caused by the complexity of the wastewater matrix and to increase the accuracy of the analytical results. Percent recovery results varied between 85.9 and 120.9% with small percent relative standard deviation values. These results were satisfactory in terms of the accuracy and applicability of the proposed method for wastewater samples.

Cloud Point Microextraction Prior to Flame-Atomic Absorption Spectrometry for the Determination of Zinc Ethylene-1,2-Bisdithiocarbamate (Zineb) in Food and Environmental Samples

Cloud point microextraction (CPME) with Triton X-114, as a nonionic surfactant, was applied for the extraction of zinc ethylene-1,2-bisdithiocarbamate (zineb) prior to its determination by flame-atomic absorption spectrometry (FAAS). The optimum CPME conditions were obtained with 250 µL of Triton X-114 at a cloud point temperature of 30 °C in 20.0 mL of the sample solution whose pH had been adjusted to 7.00. Zineb was monitored at a wavelength of 213.0 nm. The limits of detection were found to range between 13.0 and 25.0 ng mL−1 and the coefficients of determination (R2) of the calibration graphs were between 0.9975 and 0.9994. The developed CPME-FAAS method was applied to extract and determine in food and environmental samples with percentage relative recoveries ranging from 90.6 to 105.4% with percentage relative standard deviations (%RSD) less than 7.5%.

Uji Performa Alat Vakum Tekan Termodifikasi Untuk Impregnasi Kayu

The impregnation process is carried out to increase the resistance of wood from the attack of microorganisms such as fungi and termite attacks by placing the wood in a vacuum tube and then placing an impregnan solution into it. The limited ability of impregnation tubes is an obstacle in carrying out research and practicum activities, therefore there needs to be modifications to the impregnation tube so that the impregnation process can provide better results. Verification of the results of impregnation is done by calculating the value of weight percent gain (WPG) and relative standard deviation (%RSD) for the test of the level of appreciation. Based on the results of the experiment the highest %WPG value in the water impregnan solution was obtained from the parameter conditions of the type 3 press vacuum tool, which is with a time of 1 hour and a pressure of 5 bars and is worth (178.29±10.97). The highest %WPG value in boron solution of 5% is obtained from the condition of the type 6 press vacuum tool with a time of 3 hours and a pressure of 5 bars and is worth (5.16±0.45). The smallest %RSD value of water impregnan solution is achieved under the parameter conditions of type 4 tools at 3 hours and pressure 1 bar and is worth 3.99%. The smallest %RSD value of boron impregnan solution is 5% achieved under the parameter conditions of type 2 tools, namely within 1 hour and pressure of 3 bars and is worth 5.36%.

Zinc Oxide Nanomaterial‐Based Dispersive Solid Phase Extraction for the Trace Determination of Gold in Flash Gold Plating Solution Samples using Flame Atomic Absorption Spectrophotometry

AbstractThe noble metal Au is extensively used in jewelry, industry, and medicine. In order to mitigate the low sensitivity of the flame module atomic absorption spectrometer (FAAS) to determine the gold, zinc oxide (ZnO) nanomaterial were synthesized and used to pretreatment of the sample and preconcentrate gold ions in dispersive solid phase extraction (DSPE) process. Enrichment factor of the extraction method was enhanced by performing buffer solution type/volume, nanomaterial amount, mixing type/period, and desorption solvent concentration/volume optimizations. Calibration plot displayed good linearity and percent relative standard deviation recorded for the lowest concentration of the plot was adequately low (&lt;7.0 %). Dynamic dynamic range for the proposed method was calculated between 30–400 μg/L. Regression coefficient (R2) of proposed method was found to be 0.9956. With an enrichment factor of 44.5‐folds, method recorded a detection limit (LOD) of 7.4 μg L−1 and quantification limit (LOQ) of 24.8 μg L−1. Flash gold plating bath solution was used to certify the quantification accuracy/applicability in complex matrix of the method. The obtained results (1.86±0.08 g L−1) were compatible with the results of the reference method (ICP‐OES) (1.87±0.08 g L−1). This is the first study for the extraction/preconcentration of gold using ZnO nanomaterial.